The present invention pertains to acetabular reamer cups and more particularly pertains to a disposable acetabular reamer cup.
Acetabular reamers are surgical tools, which are used to cut hemispherical cavities in pelvis bones for the insertion of artificial hip joints. An acetabular reamer is composed of an acetabular reamer cup mounted on a tool driver, which in turn is mounted in the chuck or collet of a portable drill or flexible powered shaft. Acetabular reamer cups have a complex arrangement of precisely shaped cutting surfaces extending outwardly from an essentially hemispherical shell. Acetabular reamer cups are separable from their tool drivers for changing cup size prior to or during surgery, cleaning, and/or sharpening.
Acetabular reamers must be capable of producing cavities with very close tolerances and must also minimize any risk of causing contamination. Acetabular reamer cups have precise dimensions and are light in weight and must fit on an appropriate tool driver with a minimum of free play and must be quick and easy to install and remove without tools. Prior acetabular reamer cups must be cleaned after each use. Thus, the desirability of a disposable reamer cup.
Some previous acetabular reamers have used an open-bottom acetabular reamer cup gripped by the tool driver by means of a flange and slot and an opposed spring-loaded ball catch, like that on a socket wrench or socket driver. This presents a problem in that the catch tends to trap dried blood, which is very difficult to remove during cleaning. An additional problem is that unless tolerances of cups and tool drivers are made very close, at great cost, there is considerable free play between a cup and its tool driver. This increases wear and decreases the precision of the tool.
An alternative acetabular reamer, described in U.S. Pat. No. 4,811.632, utilizes a convex-bottomed acetabular reamer cup having a large central opening complementary in shape to a flange on the tool driver. Since the tool driver also grips the cup with a clamping action, extremely close tolerances are not required to prevent free play between the cup and driver. The convex bottom of the cup eliminates any internal ninety degree angles which could catch contaminants and the large central opening permits easy cleaning. The acetabular reamer cup is, however, complex in shape and expensive and, like all acetabular reamer cups, difficult to resharpen and must be cleaned between uses.
It is therefore highly desirable to provide an improved acetabular reamer cup.
t is also highly desirable to provide an improved acetabular reamer cup which is disposable and fits on a to driver with a minimum of free play.
It is also highly desirable to provide an improved acetabular reamer cup which is disposable and precise in size, light in weight and inexpensive.
it is also highly desirable to provide an improved acetabular reamer cup which is disposable and quick and easy to install and remove from a tool driver without tools.
It is finally highly desirable to provide an improved disposable acetabular reamer cup which meets all of the above desired features.